Skin is the largest organ of the human body, representing approximately 16% of a person's total body weight. Because it interfaces with the environment, skin acts as an anatomical barrier to pathogens and other environmental substances. Skin also provides a semi-permeable barrier that prevents excessive fluid loss while ensuring that essential nutrients are not washed out of the body. Other functions of skin include insulation, temperature regulation, and sensation. Skin tissue may be subject to many forms of damage, including burns, trauma, disease, and depigmentation (e.g., vitiligo).
Skin grafts are often used to repair skin damage. Traditional skin grafting is a surgical procedure in which a section of skin is removed from one area of a person's body (autograft), removed from another human source (allograft), or removed from another animal (xenograft), and transplanted to a recipient site of a patient, such as a wound site. As with any surgical procedure, skin grafting involves certain risks. Complications may include graft failure, rejection of the skin graft, infections at donor or recipient site, or autograft donor sites oozing fluid and blood as they heal. Certain of these complications (e.g., graft failure and rejection of the skin graft) may be mitigated by using an autograft instead of an allograft or a xenograft.
A problem encountered when using an autograft is that skin is taken from another area of a person's body to produce the graft, resulting in trauma and wound generation at the donor site. Generally, the size of the graft matches the size of the recipient site, and thus a large recipient site requires removal of a large section of skin from a donor site, leading to increased pain and discomfort and longer healing time. Additionally, as the size of the section of skin removed from the donor site increases, so does the possibility of infection.
Moreover, skin grafts are often difficult to obtain due to the tendency of the skin layer being cut to curl or fold over onto itself or the surgical instrument (e.g., dermatome), thereby comprising the integrity of the graft and making it unsuitable for use. This folding/curling tendency is particularly problematic the thinner the layer is that is being obtained, such as the epidermal layer.
While techniques have been developed for obtaining smaller micrografts that can be transferred onto a substrate for expansion prior to transplantation, such micrografts tend to clump together or can flip or fold during cutting, thereby comprising the integrity of the micrograft such that it will not properly grow on the substrate. As such, multiple cutting attempts are often necessary before a suitable, planar graft or micrograft is obtained, thereby producing multiple wound sites, leading to extreme discomfort, longer healing time, and a greater risk of infection.